Self-Setting Analog Clocks
The ADC-5100 series clocks are designed to combine the advantages of large, easily read analog time displays with the self-setting capability of digital SMPTE/EBU serial time code readers. This advanced mode is made possible by a unique digitally controlled drive mechanism. A microprocessor is used to decode the digital information and precisely position the hands.

In addition to SMPTE/EBU time code, the clocks can operate on the internal quartz time base, or from the 50/60 Hz power line. This three-way reference capability allows easy integration into new or existing clock systems.

The clocks are available in a variety of sizes for wall- or rack-mounting. Wall-mount models can be easily adapted to rack-mount. The standard clock face has two sets of numerals, i.e., 1 ... 12 in black and 13 ... 24 in red.

Time Code Operation
Clock installation is simple when SMPTE or EBU format time code is available. Apply power, connect time code, and the clock takes care of the rest.

On initial power-up, the clock will start to run at whatever time the hands indicate. The error LED at the bottom of the clock face is illuminated. When time code is connected, the processor moves the hands the shortest distance to the correct time. Once the clock is set, the error LED is turned off. This process takes less than 15 minutes.

If time code fails, the error LED flashes, and the clock automatically switches to the preselected secondary reference. This can be the internal quartz time base or power line. Any time discrepancy on return of time code causes the hands to move directly to the correct position. This also applies to time code changes, such as Standard Time to Daylight Savings Time.

Time Offsets
The Harris CSD-3902 master clock system driver allows programming of time code user bits. This facility can be used to include a specific time offset in the time code. The operating mode of one or more ADCs in a system can then be set to read this offset. A typical application is the display of GMT in addition to local time.

Additionally, ADCs may be preset to display an offset from local time. This local offset allows the display of any or all time zones at one location. This offset is user-programmable.

Master Operation
When no source of time code is available, the ADC may be configured as a time code generator, using its internal quartz crystal. An internal cable change is all that is required. The secondary reference must be set to internal, and the time code format DIP Switch must select either SMPTE or EBU format.

When used as a generator, the ADC can drive multiple high-impedance, time-code-reading devices.

Secondary Drives
The internal crystal oscillator or the power line reference may be selected to provide automatic back-up if time code fails. Either time base can also be used to run the clock as a standalone device, when necessary. The ADC automatically detects the presence of 50 or 60 Hz power line frequency.

Battery Back-up
If AC power is lost, the ADC maintains time internally via a crystal oscillator. Self-setting to this time will occur if no input time code is available on power-up.

REAR PANEL FACILITIES

Primary Drive Connectors
The rear panel input connectors for time code are color-coded (red/black), spring-loaded, speaker-type connectors. A standard three-prong AC receptacle is also provided.

Mode Configuration A six-position DIP switch is used to set the clocks operating modes. The first switch selects the primary drive. The second switch selects SMPTE or EBU time code format for use when operating as a generator. The third switch selects the secondary drive, which will be used if the time code input fails. The secondary reference may be the internal quartz crystal oscillator or AC power line. The fourth switch selects either normal time code operation or time offset (requires time code from CSD-3902). This allows certain clocks in the system to display a different time, according to an offset programmed into the user bits of the time code. The fifth switch specifies whether the clock should run from the preselected primary or secondary drive. The sixth switch is used to select a step or sweep second hand. 115 or 230 VAC selection is made via internal wire jumpers; 50 or 60 Hz detection is automatic.

Manual Setting
When operating in a mode other than time code, the clock can be accurately set by means of three miniature pushbuttons on the rear panel. One of the buttons selects the manual set mode. The other two buttons move the hands clockwise or counterclockwise in appropriate increments. These buttons are also used to program a local offset from time code.